Patent GB-607118-A (GB)
Title: Improvements in or relating to photographic copying and reproducing apparatus
IPC: G03B27/465
Filed: 1944-08-03
Abstract: 607,118. Photographic projection-printing apparatus. TRIGGS, W. W. (Microstat Corporation). Aug. 3, 1944, No. 14854. [A Specification was laid open to inspection under Sect. 91 of the Acts, June 25, 1947.] [Class 98 (i)] The carriage of a photographic reproducing camera is moved up and down a vertical column by means of a reversible electric motor and a flexible connecting member, the latter being connected to a scale, the amount projecting above the camera table indicating the distance of the camera from the table for focusing purposes. The movable camera portion 42 is carried on a carriage 41 movable vertically on a tubular column 40 and is controlled and driven by a roller chain 91 secured to the upper and lower ends of the carriage and passing over idler sprockets 92, 93 at the ends of column 40 and over a sprocket 90 on a reversible motor 87. A turn buckle 95 adjusts the tension in the chain and a measuring tape 96 connected to the latter indicates visually the height of the camera above the table 34. The lens barrel 47 is threaded and keyed in a sleeve 45 and is adjusted by means of a reversible motor 54 meshing with a worm gear 56 and a gear ring 46 on the lens assembly. A counter indicates the setting. A lever 53 controls the iris diaphragm. The assembly comprising the condenser lens system 64, a mirror 67 and lamp 65 is enclosed in a pivoted housing 62. A light shield 71 pivoted at 72 is connected to the housing 62 by means of a pivoted rod 74. A film control and shutter assembly 61 is driven from a motor 77 which has a suitable speedreducing gear head 78, a shaft 80 and jaw coupling 81. The shaft 80 carries two cams 82, 83 which control switches 84, 85. Film magazines with detachable fronts (not shown) are attached to the sides of the camera portion 42. The film 107 passes through slots 109, 110 in the sub-assembly 61, and under a pressure plate 113 held in the trunnioned frame 114. The yoke 117 has its shank 118 loosely pivoted to the top of a plunger 119 which is moved up and down by a lever 126 pivoted at 127 and passing through a slot in the lower end of the pin 119. A cam 128 on the drive shaft 79 rocks the lever 126, moving the pressure plate into and out of engagement with the film 107 and the gate 111. The film is driven by a toothed sprocket 130, a drive pin 134 in the rear end of the spool engaging selectively in holes 136 in an annular driving member 135 slidably mounted on a shaft 129. The member 135 may be moved against the spring 137 out of engagement with the pin 136 and secured by a bayonet slot 140, thus permitting free movement of the film 107. A clutch plate 142 connects with the shaft 129 which is driven by gears 146, 147 secured to the drive shaft 79. The gear 147 carries at its sides two cams 128, 148. The clutch plate 142 has in its periphery two oppositely placed notches 149, 150 adapted to receive a detent 151 on a pivoted lever 152. The cam 148 acts to withdraw the detent from engagement with the notches. The entry of the detent into the notches also rocks a pawl 155 out of engagement with the ratchet 143, either by direct action or through two articulated links 161, 162, whereby the plate 142 is held whilst the ratchet and its shaft continue to rotate. Consequently, once during each revolution of shaft 79, the plate 142 and sprocket 130 are driven one half revolution feeding the film forward one frame, the cam 128 ensuring release of the pressure plate 113. A guide shoe 133 and roller 164 are positioned to avoid abrasion of the film. A spring-friction belt 166 connected to the film reel provides a yielding take-up drive. The sectored shutter disc 168 is rotatably mounted on the bottom plate 169 and is driven from the shaft 79 via mitre gears 170, 171, exposure taking place when the film is stationary and held flat by the pressure plate. Illumination for photography is by lights 194, Fig. 24, held on brackets. Limit switches 195, 196 on the carriage 41 engage abutments 197, 200 on the column 40, Fig. 5, so as to disconnect the motor circuit when the carriage reaches the extreme positions. The electrical circuit supplying and controlling the apparatus is shown in Fig. 24. The three-pole double-throw switch 179 controls the elevating motor 87, the limit switches when opened breaking the motor circuit. A time switch 183 with a shunted manual switch 178 controls the projection lamp 65. The shutter motor 77 may be energized from a foot switch 201 or via the cam switch 84 and manual switch 177. In projection printing, the toggle switch is open and prevents operation of the shutter. A second cam switch 85 controls the signal lamp 203. The focusing motor is connected through the reversing switch 180 and push-button 182. By selective operation of switches, the camera may be used for photographing documents &c. or for reproductions, the subjects being either singly or in series. Specification 607,193 is referred to.